JP3352922B2 - Vortex pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vortex pump used, for example, for supplying sewage in a water treatment apparatus, and more particularly to a vortex pump having a shaft power provided with a limit load property while maintaining pump efficiency. Things.

[0002]

2. Description of the Related Art Vortex pumps are widely used as sewage / filtration pumps because there is a large gap between the bottom surface of the impeller blades and the bottom surface of the casing, and there is little occurrence of blockage accidents in the pump due to foreign matter. It is used.

FIG. 9 shows the structure of a conventional general vortex pump. This is a motor unit 2 that drives the spindle 1.
And a pump unit 3 for pumping water by the rotation of the main shaft 1. Then, the pump unit 3 and the motor unit 2 are controlled so that the pressure water of the pump unit 3 does not leak to the motor unit 2 side.
The space between them is double-sealed with an upper mechanical seal 4a and a lower mechanical seal 4b.

In the motor section 2, a rotor 5 rotating integrally with the main shaft 1 and a stator 7 having a stator winding 6 are housed in a motor chamber 8. This motor room 8
Is a substantially cylindrical motor frame 10 opened upward and a motor cover 11 connected to an upper end of the motor frame 10.
And an underwater cable 12 is connected to the upper part.

The main shaft 1 is connected to an upper bearing 13 attached to the motor cover 11 and the motor frame 10.
Is rotatably supported via a lower bearing 15 attached to the inner peripheral surface of a load-side bracket 14 connected to the lower end of the bracket.
Further, on the upper surface of the motor cover 11, a handle 16 for suspending or moving to a spring site is provided.

On the other hand, the pump section 3 includes a plurality of blades 20.
And a vortex impeller 21 connected to the tip of the main shaft 1 so as to rotate integrally therewith. The impeller 21 has a discharge port 22a and a suction port 22b,
The inside is covered with a pump casing 22 having a pump chamber 23 so that spring water or the like at a construction site is sucked from a lower portion and discharged from a side surface. Here, a discharge curved pipe 24 is connected to the discharge port 22a.

[0007] Between the lower end surface of the blade 20 of the impeller 21 and the bottom surface of the pump casing 22, there is provided a wide gap which is characteristic of a vortex type pump, so that even relatively large foreign matter can be easily discharged. I can do it. The pump casing 22 is provided with a pump stand 25 that allows the pump to stand on its own.

The mechanical seals 4a and 4b are disposed in a mechanical seal chamber 31 defined by an intermediate casing 30 connecting the load-side bracket 14 and the pump casing 22 and the load-side bracket 14. The part is filled with oil for lubricating and cooling the sliding surface of the mechanical seal. Also, the mechanical seal 4a,
In order to prolong the life of 4b, an oil seal 32 is incorporated between the intermediate casing 30 and the boss of the impeller 21 to prevent foreign matter such as sand from approaching the mechanical seal sliding surface.

Here, as shown in FIGS. 10 and 11,
Blade angle (entrance angle) on the inlet side of blade 20 of impeller 21
β ₁ and the exit side blade angle (exit angle) β ₂ are, for example, 3
In 0 to 45 °, with the blade angle over the entire length of the blade 20 is set to be substantially constant, the planar shape of each wing 20, for example a plurality of arc such radius R ₁ and radius R ₂ Is defined.

FIG. 12 shows a pump characteristic curve of this type of vortex pump. As shown in the figure, although the shaft power increases with an increase in the pump water pumping amount, it can be seen that the shaft power does not have a characteristic of being saturated or reduced at a certain flow rate or more (limit load characteristic).

[0011]

As described above, in the conventional vortex type pump, since the limit load characteristic is not seen, when a pump having a higher head than the pipe resistance is selected, An excessive flow rate will flow. For this reason, the motor is operated at an output exceeding the rated output of the motor during the excessive flow rate operation, and there is a problem that the motor may be burned out or the motor protection device may be operated so that the motor may not be continuously operated.

As a measure for imparting the limit load characteristic with a vortex pump and a general centrifugal pump, a blade angle on the outlet side of a blade of an impeller (exit angle) has conventionally been used.
Was being lowered. However, in the case of the conventional vortex pump, if the exit angle of the blade is set low so that sufficient limit load characteristics can be obtained,
There is a drawback that the pump efficiency is significantly reduced, and it has been difficult to achieve high limit load characteristics while maintaining pump performance.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a vortex type pump capable of imparting a limit load property to a shaft power characteristic while maintaining a constant pump efficiency. I do.

[0014]

A vortex pump according to the present invention is a pump casing having a circular cross section for accommodating an impeller.
The pump casing is provided inside the pump casing.
Vortex type that forms a flow path by rotation
In the pump, the blade angle on the inlet side is set to 0 ° and the blade angle on the outlet side is set to 17.5 to 32.5 °, and the blade angles rise from the inlet side and are smoothly connected to the outlet side. And an impeller having:

[0015] Thus, the blade angle on the outlet side (exit angle) of each blade is reduced to give a limit load characteristic, and the outlet angle is smoothly raised from 0 ° on the inlet side. By increasing, it is possible to prevent a decrease in pump efficiency. Here, it is preferable that the plane shape of the blade is formed by a straight line having a blade angle of 0 ° on the inlet side and a plurality of arcs continuously extending from the straight line to the outlet side.

[0016] Before it is preferable to set the ratio to 1.15 or more with respect to the outer diameter of the impeller diameter of the circular flow path Kipo pump casing, thereby further improving the limit load characteristics of the pump Can be.

Further, it is preferable that the blade width of the impeller is set to 68% or more of the maximum passage diameter of the foreign matter inside the pump, so that the foreign matter passage and the pump efficiency can be achieved in a well-balanced manner.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vortex pump according to the present invention will be described below with reference to FIGS.
The same parts as those of the conventional example shown in FIGS. 9 to 11 are denoted by the same reference numerals, and the description thereof will be omitted.

In this embodiment, as shown in FIG. 1, a vortex-type impeller having a plurality of blades 40 in a pump section 3 and connected to the tip of a main shaft 1 so as to rotate integrally therewith. The basic structure provided with 41 is the same as that of the prior art. The impeller 41 is covered by a pump casing 42 having a discharge port 42 a and a suction port 42 b and supported by a pump stand 45, and is housed in a pump chamber 43. The structure in which spring water or the like at a construction site is sucked in from the lower part of the pump casing 42 and discharged from the side surface thereof is also the same as the conventional technology.

Here, in the present invention, each of the wings 40
As shown in wing development view of FIG. 4, in that the blade angle (entrance angle) of the inlet-side alpha ₁ is 0 °, the blade angle (exit angle) of the outlet alpha ₂ is from 17.5 to 32.5 ° Are set to
The blades 40 are formed such that the blade angles are smoothly connected over the entire length. That is, the inlet angle on the inflow side of the blade 40 is set to 0 °.
The blade angle rises from the inlet angle of 0 ° and is continuously connected by an arc so as to smoothly connect to the outlet angle of 17.5 to 32.5 °.

The plane shape of each wing 40 is shown in FIG.
As shown in, it is defined at the inlet side of the blade angle (entrance angle) 0 and the straight line 40a of °, arc 40b of radius R ₃ and the radius R ₄ extending continuously from the straight line 40a on the outlet side. In this embodiment, the plane shape of the wing 40 is 2
Although the example defined by three arcs is shown, it may be defined by three or more arcs.

The reason why the inlet angle α ₁ of the blade 40 is set to 0 and the outlet angle α ₂ is set to 17.5 to 32.5 ° is as follows. That is, FIG. 6 shows an example of a change in the pump characteristics accompanying a change in the exit angle of the blade (the angle β ₂ in FIG. 10), and (a) shows the flow rate-head (QH).
(B) shows the relationship between the flow rate and the shaft output.
Note that the entrance angle α ₁ is 0 °. According to the figure, when the exit angle of the blade is 45 °, the limit load characteristic is not obtained in the shaft power, and when the exit angle of the blade is smaller than 30 °, the limit load characteristic is recognized. It is recognized that the limit load property increases as the size decreases. However, it can be seen that as the exit angle of the blade becomes smaller, the flow rate-head characteristic of the pump also decreases.

As a result, the exit angle α ₂ of the wing 40 becomes 3
By setting the angle to 2.5 ° or less, a limit load characteristic can be given to the shaft power. Further, by setting the outlet angle α ₂ of the blade 40 to 17.5 or more, it is possible to prevent a decrease in pump efficiency. By increasing the blade angle from the inlet angle of 0 ° to the outlet angle so as to be connected smoothly, it is possible to prevent the pump efficiency from decreasing while providing the limit load characteristic.

The maximum diameter (maximum passage diameter) of the foreign matter that can pass through the inside of the pump is determined by the diameter of the narrowest part of the pump in the pump (usually formed by the tip of the impeller blade and the bottom of the pump casing). Flow path width). In this embodiment, the width H (see FIG. 3) of the blade 40 of the impeller 41 is set to be 0. 0 to the maximum diameter D ₁ (see FIG. 3) of the foreign matter.
Is set in a range of 68D ₁ or more (H> 0.68D _1).

That is, FIG. 7 shows a change in the pump performance when the blade width H of the impeller is changed. FIG. 7 shows that the blade width H of the impeller when the maximum passage diameter D ₁ is 100 mm is 7 mm.
5 mm (H = 0.75D ₁ ) and 100 mm (H = 1.
00D ₁ ), the blade width H of the impeller is 50 mm
(H = 0.5D ₁ ) shows that the pump efficiency is greatly reduced. From such test results, by setting the width H of the blades 40 of the impeller 41 in a range of 0.68D ₁ or more with respect to the maximum passage diameter D ₁ of the foreign substance (H> 0.68D _1), foreign matter while ensuring the maximum passage diameter D _1, it is possible to prevent a decrease in pump efficiency.

In this embodiment, a pump casing 42 having a circular cross section is used.
₃ (see FIG. 3) with respect to the outer diameter D ₂ (see FIG. 3) of the impeller 41 with a ratio D ₃ / D ₂ of 1.15 or more (D ₃ / D ₂ > 1.
15).

That is, FIG. 8 shows a ratio D ₃ / D of the diameter D ₃ of the circular cross section of the pump casing 42 to the outer diameter D ₂ of the impeller 41.
The figure shows the difference in pump performance due to the difference between the _two , and it can be seen from the figure that when D ₃ / D ₂ is small, the limit load property of the pump is reduced, and the power of the pump shaft increases to the right. From such test results, it is possible to further improve the limit load characteristics of the pump by setting the ratio of D ₃ / D ₂ to 1.15 or more.

FIG. 5 shows an example of the performance of the vortex pump in the above embodiment. FIG. 12 and FIG.
Compared with the conventional pump characteristic curve shown in FIG. 5, it can be seen that the limit load characteristic of the vortex pump of this embodiment is greatly improved. In addition,
FIG. 5 shows an example in which the rated output is applied to a power of 7.5 kW, but a complete limit load property is obtained for the power of 7.5 kW, and the pump efficiency and the flow rate-head performance are also conventional. It turns out that the performance exceeding the product is obtained.

[0029]

As described above, according to the present invention, it is possible to realize the limit load characteristic with the same efficiency as the conventional vortex pump. Therefore, when a pump having a higher head than the pipe resistance is installed at the site, the output of the motor is limited even in the case of an excessive flow rate operation, so that the motor burnout or the motor protection device operates. The problem that continuous operation cannot be performed can be prevented.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of a vortex pump according to an embodiment of the present invention.

FIG. 2 is a plan view of the impeller.

FIG. 3 is a sectional view showing the relative positions of the pump casing and the impeller in the axial direction.

FIG. 4 is a wing development view of the impeller.

FIG. 5 is a graph showing an example of pump performance.

FIG. 6 is a graph showing an example of a change in pump performance with a change in the outlet angle of the blade.

FIG. 7 is a graph showing an example of a change in pump performance when the blade width of an impeller is changed.

FIG. 8 is a graph showing a difference in pump performance due to a difference in a ratio of the diameter D ₃ of the circular cross section of the pump casing to the outer diameter D ₂ of the impeller.

FIG. 9 is a vertical sectional front view showing a conventional vortex pump.

FIG. 10 is a front view of the impeller.

FIG. 11 is a sectional view showing the relative positions of the pump casing and the impeller in the axial direction.

FIG. 12 is also a graph showing an example of pump performance.

[Explanation of symbols]

1 spindle 2 motor 3 blade angle (entrance angle) of the pump portion 5 rotor 7 stator 40 blades 41 impeller 42 pump casing 43 the pump chamber alpha ₁ inlet side alpha ₂ outlet side of the blade angle (exit angle) H wingspan D ₁ Maximum passing diameter of foreign matter D ₂ Outer diameter of impeller D ₃ Diameter of circular cross section of pump casing

Continuation of front page (56) References JP-A-9-195986 (JP, A) JP-A-9-32791 (JP, A) JP-A-3-130598 (JP, A) JP-A-47-13703 (JP) JP-A-55-7967 (JP, A) JP-A-56-101496 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04D 7/04 F04D 29/24

Claims (4)

(57) [Claims] (1)Pump housing with a circular cross section for storing the impeller
The pump casing inside the pump casing.
Vortex that forms a flow path by the rotation of the car
Type pump,  The blade angle on the inlet side is 0 ° and the blade angle on the outlet side is 17.5 to
32.5 ° and the wing angle stands from the inlet side
Has wings that go up and connect smoothly to the exit side
Vortex type pon with impeller
H. 2. The plane shape of the blade according to claim 1, wherein the blade is formed by a straight line having a blade angle of 0 ° on the inlet side and a plurality of arcs extending continuously from the straight line to the outlet side. Vortex pump. 3. Before Kipo pump according to claim 1 or 2 Vortex pump according to characterized in that the ratio of the outer diameter of the impeller diameter of the circular flow path set to 1.15 or more casing. 4. The vortex pump according to claim 1, wherein a blade width of the impeller is set to 68% or more of a maximum passage diameter of foreign matter inside the pump.